Islamist militants waging a brutal insurgency in northern Mozambique have abducted more than 600 women and children over the past three years, Human Rights Watch said in report Tuesday.

“An armed group linked to the Islamic State (ISIS) has since 2018 kidnapped and enslaved more than 600 women and girls in Mozambique’s northern Cabo Delgado province,” the rights group said in a statement.

Some have been freed by Mozambican and foreign forces deployed this year to help quell the violence that has wreaked havoc in the region since October 2017.